Re: [PATCH] mm/damon/sysfs: change few functions execute order

[haoxin <xhao@linux.alibaba.com>]

在 2022/9/10 上午6:44, Andrew Morton 写道:
> On Thu,  8 Sep 2022 22:16:53 +0000 SeongJae Park <sj@kernel.org> wrote:
>
>> Reviewed-by: SeongJae Park <sj@kernel.org>
> Cool.  I rewrote the changelog significantly:

Thanks for all of your hard work and detailed review !

>
> From: Xin Hao <xhao@linux.alibaba.com>
> Subject: mm/damon/sysfs: change few functions execute order
> Date: Thu, 8 Sep 2022 16:19:32 +0800
>
> There's no need to run container_of() as early as we do.
>
> The compiler figures this out, but the resulting code is more readable.
>
> Link: https://lkml.kernel.org/r/20220908081932.77370-1-xhao@linux.alibaba.com
> Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
> Reviewed-by: SeongJae Park <sj@kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>   mm/damon/sysfs.c |   24 ++++++++++++++----------
>   1 file changed, 14 insertions(+), 10 deletions(-)
>
> --- a/mm/damon/sysfs.c~mm-damon-sysfs-change-few-functions-execute-order
> +++ a/mm/damon/sysfs.c
> @@ -1031,8 +1031,7 @@ static ssize_t nr_schemes_show(struct ko
>   static ssize_t nr_schemes_store(struct kobject *kobj,
>   		struct kobj_attribute *attr, const char *buf, size_t count)
>   {
> -	struct damon_sysfs_schemes *schemes = container_of(kobj,
> -			struct damon_sysfs_schemes, kobj);
> +	struct damon_sysfs_schemes *schemes;
>   	int nr, err = kstrtoint(buf, 0, &nr);
>   
>   	if (err)
> @@ -1040,6 +1039,8 @@ static ssize_t nr_schemes_store(struct k
>   	if (nr < 0)
>   		return -EINVAL;
>   
> +	schemes = container_of(kobj, struct damon_sysfs_schemes, kobj);
> +
>   	if (!mutex_trylock(&damon_sysfs_lock))
>   		return -EBUSY;
>   	err = damon_sysfs_schemes_add_dirs(schemes, nr);
> @@ -1237,8 +1238,7 @@ static ssize_t nr_regions_show(struct ko
>   static ssize_t nr_regions_store(struct kobject *kobj,
>   		struct kobj_attribute *attr, const char *buf, size_t count)
>   {
> -	struct damon_sysfs_regions *regions = container_of(kobj,
> -			struct damon_sysfs_regions, kobj);
> +	struct damon_sysfs_regions *regions;
>   	int nr, err = kstrtoint(buf, 0, &nr);
>   
>   	if (err)
> @@ -1246,6 +1246,8 @@ static ssize_t nr_regions_store(struct k
>   	if (nr < 0)
>   		return -EINVAL;
>   
> +	regions = container_of(kobj, struct damon_sysfs_regions, kobj);
> +
>   	if (!mutex_trylock(&damon_sysfs_lock))
>   		return -EBUSY;
>   	err = damon_sysfs_regions_add_dirs(regions, nr);
> @@ -1440,8 +1442,7 @@ static ssize_t nr_targets_show(struct ko
>   static ssize_t nr_targets_store(struct kobject *kobj,
>   		struct kobj_attribute *attr, const char *buf, size_t count)
>   {
> -	struct damon_sysfs_targets *targets = container_of(kobj,
> -			struct damon_sysfs_targets, kobj);
> +	struct damon_sysfs_targets *targets;
>   	int nr, err = kstrtoint(buf, 0, &nr);
>   
>   	if (err)
> @@ -1449,6 +1450,8 @@ static ssize_t nr_targets_store(struct k
>   	if (nr < 0)
>   		return -EINVAL;
>   
> +	targets = container_of(kobj, struct damon_sysfs_targets, kobj);
> +
>   	if (!mutex_trylock(&damon_sysfs_lock))
>   		return -EBUSY;
>   	err = damon_sysfs_targets_add_dirs(targets, nr);
> @@ -1962,8 +1965,7 @@ static ssize_t nr_contexts_show(struct k
>   static ssize_t nr_contexts_store(struct kobject *kobj,
>   		struct kobj_attribute *attr, const char *buf, size_t count)
>   {
> -	struct damon_sysfs_contexts *contexts = container_of(kobj,
> -			struct damon_sysfs_contexts, kobj);
> +	struct damon_sysfs_contexts *contexts;
>   	int nr, err;
>   
>   	err = kstrtoint(buf, 0, &nr);
> @@ -1973,6 +1975,7 @@ static ssize_t nr_contexts_store(struct
>   	if (nr < 0 || 1 < nr)
>   		return -EINVAL;
>   
> +	contexts = container_of(kobj, struct damon_sysfs_contexts, kobj);
>   	if (!mutex_trylock(&damon_sysfs_lock))
>   		return -EBUSY;
>   	err = damon_sysfs_contexts_add_dirs(contexts, nr);
> @@ -2737,8 +2740,7 @@ static ssize_t nr_kdamonds_show(struct k
>   static ssize_t nr_kdamonds_store(struct kobject *kobj,
>   		struct kobj_attribute *attr, const char *buf, size_t count)
>   {
> -	struct damon_sysfs_kdamonds *kdamonds = container_of(kobj,
> -			struct damon_sysfs_kdamonds, kobj);
> +	struct damon_sysfs_kdamonds *kdamonds;
>   	int nr, err;
>   
>   	err = kstrtoint(buf, 0, &nr);
> @@ -2747,6 +2749,8 @@ static ssize_t nr_kdamonds_store(struct
>   	if (nr < 0)
>   		return -EINVAL;
>   
> +	kdamonds = container_of(kobj, struct damon_sysfs_kdamonds, kobj);
> +
>   	if (!mutex_trylock(&damon_sysfs_lock))
>   		return -EBUSY;
>   	err = damon_sysfs_kdamonds_add_dirs(kdamonds, nr);
> _